From 27032e002fb51fc5554145cef1a54fba2b32505f Mon Sep 17 00:00:00 2001
From: Carlo Cabrera <30379873+carlocab@users.noreply.github.com>
Date: Tue, 18 Jul 2023 20:47:10 +0800
Subject: [PATCH] os/mac/keg_relocate: avoid changing to an already existing
 rpath

Doing `change_rpath(old, new, file)` will error if `new` is already an
rpath for `file`. When this happens, `old` is no longer needed, so we
can delete it.

Fixes a build failure at shivammathur/homebrew-php#1848.
---
 Library/Homebrew/extend/os/mac/keg_relocate.rb | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/extend/os/mac/keg_relocate.rb b/Library/Homebrew/extend/os/mac/keg_relocate.rb
index 1667c1e016..6ad9c06d08 100644
--- a/Library/Homebrew/extend/os/mac/keg_relocate.rb
+++ b/Library/Homebrew/extend/os/mac/keg_relocate.rb
@@ -62,7 +62,15 @@ class Keg
           else
             new_name = opt_name_for(bad_name)
             loader_name = loader_name_for(file, new_name)
-            change_rpath(bad_name, loader_name, file) if loader_name != bad_name
+            next if loader_name == bad_name
+
+            if file.rpaths(resolve_variable_references: false).include?(loader_name)
+              # The wanted loader_name is already an rpath, so the existing bad_name is not needed.
+              # Attempting to change bad_name to an already existing rpath will produce an error.
+              delete_rpath(bad_name, file)
+            else
+              change_rpath(bad_name, loader_name, file)
+            end
           end
         end
       end